1. Field of the Invention
This invention relates to an output method and apparatus for outputting an image in accordance with data input from an external apparatus, such as a host computer or the like.
2. Description of the Related Art
FIG. 2 is a block diagram showing the flow of processing in a control unit 1 of a conventional output apparatus such as a printing apparatus.
In FIG. 2, an external apparatus 2 outputs print data from a host computer or the like. An input unit 3 receives the data. An analyzing unit 4 analyzes input data. A developing unit 5 develops data into an output image, for example, in the form of a bit-map memory according to analysis of the analyzing unit 4. A frame memory 6 stores the developed output image, and comprises a RAM (random access memory). An output unit 7 controls an output mechanism 8, such as a laser-beam printer or the like, in accordance with the data stored in the frame memory 6 so as to cause the output mechanism 8 to output the data onto recording medium 9 such as paper or the like.
In the control unit 1, print data output from the external apparatus 2 are received by the input unit 3, and are analyzed by the analyzing unit 4. According to the result of the analysis, the developing unit 5 forms an output image, for example, in the form of a binary bit-map memory for one page in the frame memory 6. The output unit 7 performs, for example, on/off control of a laser beam for the output mechanism 8 in accordance with the data stored in the frame memory 6, whereby a print result is recorded on the recording medium 9.
Because of the large memory capacity needed for frame memory 6, such a conventional approach is not satisfactory. Specifically, since data are stored in the frame memory 6 in the form of a bit-map memory or the like which is convenient for development, a very large capacity is needed for the frame memory 6. For example, if the user desires to develop a black-and-white A4-size image with a resolution of 600 dpi (dots per inch), a binary bit-map memory with a capacity of about 4 megabytes is needed for one page. In order to deal with a multivalue output or a color output, a binary bit-map memory with a capacity of several times the above-described value is needed.